Written By BiharWatch on Monday, October 27, 2008 | 3:48 AM

UNESCO publishes 1st world map of underground transboundary aquifers

UNESCO is publishing the first-ever world map of shared a quifers to coincidewith the submission to the UN General Assembly on 27 October of a draftConvention on Transboundary Aquifers, according to a press statement from theworld body here. An aquifer is an underground layer of water-bearing permeablerock or unconsolid ated materials (gravel, sand, silt, or clay) which providescolored pictures and information on why water is important and how it'sfrequently used.

Almost 96% of the planet's freshwater resources are to be found in underground aquifers, most of which straddle national boundaries.

Despite its strategic importance, no global inventory of this resource had beencompiled to date.

Since 2000, UNESCO's International Hydrological Programme (IHP) has beenparticipating in the establishment of a groundwater database.

It is now presenting a detailed map of transboundary aquifers - available online- showing the delineations of aquifers that are shared by at least twocountries.

It also provides information about the quality of their water and rate ofreplenishment.

So far, the inventory comprises 273 shared aquifers: 68 are on the Americancontinent, 38 in Africa, 65 in eastern Europe, 90 in western Europe and 12 inAsia.

The aquifers, which contain 100 times the volume of fresh water that is to befound on the Earth's surface, already supply a sizeable proportion of man'sneeds.

The growth in the demand for water since the second half of the 20th century hasbeen met by the increased use of underground resources.

Globally, 65% of this utilization is devoted to irrigation, 25% to the supply ofdrinking water and 10% to industry.

Underground aquifers account for more than 70% of the water used in the EuropeanUnion, and are often one of the only - if not the only - source of supply inarid and semi-arid zones (100% in Saudi Arabia and Malta, 95% in Tunisia and 75%in Morocco).

Irrigation systems in many countries depend very largely on groundwaterresources (90% in Libya, 89% in India, 84% in South Africa and 80% in Spain).

Although aquifer systems exist in all continents, not all of them are renewable.

For example, those in north Africa and the Arabian peninsula were formed morethan 10,000 years ago when the climate was more humid and are no longerreplenished.

In some regions, even if the aquifers are renewable - being fed on a regularbasis by rainfall - they are in some cases endangered by over-exploitation orpollution.

In the small islands and coastal zones of the Mediterranean, populations oftenuse groundwater more rapidly than it is replenished.

The aquifers in Africa, however, which are some of the biggest in the world, arestill largely under-exploited. They have considerable potential, provided thattheir resources are managed on a sustainable basis.

Since they generally extend across several State boundaries, their exploitationpresupposes agreed management mechanisms in order, for example, to preventpollution or over-exploitation by particular States.

Mechanisms of this kind have begun to emerge in recent years.

For example, in the 1990s Chad, Egypt, Libya and Sudan established a jointauthority to manage the Nubian aquifer system in a concerted manner.

In their project concerning the Iullemeden aquifer, Niger, Nigeria and Maliapproved in principle a consultative mechanism for administering the aquifersystem.

But such mechanisms are the exception.

The draft Convention on transboundary aquifers, prepared by the United NationsInternational Law Commission with the assistance of experts from UNESCO'sInterna t ional Hydrological Programme (IHP), is therefore intended to fill agap in the law.

The text to be submitted to the UN General Assembly on 27 October, calls onaquifer States not to harm existing aquifers, to cooperate and to prevent andcontrol their pollution.

The World-wide Hydrological Mapping and Assessment Programme (WHYMAP) waslaunched in 1999 to improve knowledge and management of the Earth's resources,particularly groundwater.